Vulcanized wood.



I U TED STATES PATENT.

011mm HOWARD, or nnwronk. nyyqAssronon '10 NATIONAL lamina, ironoam zme CORPQRATIOK, A conromrron or nnmwnn r vULcAmzEp 'woon sp cification of as riu ent; P te ted Mar, 26,1912.

in Drawing. Application filed October 11; 1909. Serial at 522,193. p

To all it ma Be itkno wn that 1, CHARLES Howauo, a?

citizen of jthe United States, residing at New York, in the "county of. New York and State of New York, have invented certain newand useful Improvements in Valetinized lVoods, of wh ch the following is 'a specification.

My invention relates to improvmentsin vulcanized woods, and it consists in the products herein described and claimed.

An object of my invention is to provide an improved vulcanized wood, which is thoroughly dried and. hardened throughout, with its fibers intact' from distortion and disruption and efficiently protected from the absorption of moisture, thereby insuring an unwarped product which will maintain its shape under severe; praetlealuse.

A furthenv object of my invention is to provide an improved vulcanized'wood, in which the hardened and-undecomposed resins are uniformly disposed .throughoutthe fibers of the entire mass; thereby providing a uniform, close-grained roduct ca'-' pable of a high polish, and, which will-ef-' ficiently resist all deterioration and .rotting throughthe absorption of moisture.

My invention provides a product of uniform vulcanization throughout, which is es' pecially adapted for advantageous use ander conditions in which-exposure to'the elements renders liable the accumulation and 1 retention of ater in cracks or cavities railway ties.

within the wood; such, for example, as in A preferred method of manufacturing my improved product is as follows: The wood under treatment is placed in an unheated condition in a retort, and subjected to a progressively increasing vacuum which is gradually raised to a maximum of approximately 20 to 28 inches; thereby causing a gradual and complete evaporation of all moisture and thereadily volatile matters without danger of distortion or disruption of thewood fibers. Steam, preferably below 230 F., is then admitted to the retortand maintained incontact with the 'wood for a sutlicient 'tirie'to thoroughly-penetratef the latter and moisten'and soften the'fibers thereof; "the wood being raised Iuniformly to the temperature 05f the steam. This step permits a further portion of the aqueous constituents ofthe wood to freely escape from the moistened'an'd heated fibersg'thei" resins being melted, and a portion of the pyroligneous acid removed by the steam: This step of'my process is,varied advantageouslyaccording to the character of the wood under treatment; the steam being either confined under pressure in the retort,

or circulated -either continuously .or period 'ically through theretort under pressure.

The steam is then exhausted from the retort, .and the wood subjected to the combined action ot-a vacuum and of an increased degree of dry heat, preferably below 380 F., for a sufficient-time to drive off the steam absorbed 'in thepreceding step together with the remaining pyroligneous acid, wand to distribute the resins without decomposition thereof lunifo rmly through- 4 i s out the mass of the wood. During the subjection of the wo'd to an. increased heat,

premature hardening of the outer layers is prevented by'the escape outwardly there-' through of the steam previously absorbed throughout the entire mass of the wood? thereby producing a progressive drying from the mterlor outward and permitting the penetration and distribution of the mulecomposed resins uniformly throughout the entire mass of the wood. The supply of heat 1s then cut'ott' and the wood gradually cooled under a vacuum. During th s step,

the relatively highly heated and thoroughly.

dried wood is subjected uniformly throughout its mass to a gradually decreasing tem-.

I have described a preferred and satisfactory method of mamlfacturing my im proved product, but other methods may be employed, and my invention is entirely independent thereof.

The process herein described forms the.

subject matter of my. application .lio. 522192, filed October 11, 1909.

Having thus described my invention, what I claim as new and desire to secure by Letters-Patent is: g v

1. Thehereln described product, comprising wood free from allvolati'le aqueous niat-' ,ters, and having its undecomposed T881115 deposlted uniformly throughout the hardened fibers of the entire mass.

' 2. The "herein described product, comprisfree from all volatile aqueous matters, and

having its resins disseminated in an undecomposed form uniformly throughout the entire mass.

4. The herein described product, comprising wood having its ulrdisrupted fibers deprived of pyroligneou's acid and uniformly impregnated with the hardened and undeeomposed wood resins, thereby providing an ImPI'OVQ'Cl vulcanized wood, which remains practically unchanged through long and se- 1 Vere use.

5. The herein described product, comprising wood free from all volatile aqueous matters, and havlng its gums and undecomposed resins deposited uniformly throughout the hardened fibers of the entire mass.

In testimony whereof I aflix"my signature in presence of two witnesses.

CHARLESHOWARD. Witnesses C. A. BAKER, G; AYRES. 

